Process of winding cores

ABSTRACT

In toroidal core winding apparatus, wherein the wire to be wound is stored as a helix within a hollow hoop and the hoop as it rotates through the core dispenses the wire from a point on the edge of its inner periphery; the hoop consists of a flexible hollow steel or plastic tube that can be maintained in the shape of a distorted circle; e.g., an elongated oval or racetrack shape, by guide wheels so that the hoop, for at least an appreciable portion of length on its periphery, moves in a straight line as it passes through the core, thus permitting the diameter of the tubing forming the hoop to be larger. Significant advantages of this invention are that: (a) the straight run permits the wire to be drawn down tight on the core largely along its line of travel; and (b) the wire can be wound on the core in either direction by simply reversing the direction of rotation of the hoop. Also, two strands of wire can be payed out simultaneously from the hoop. This can be done in any conventional manner. For example, motor 20 can be a reversible motor.

United States Patent [191 Sedgewick [111 3,811,629 [451 May 21, 1974Related US. Application Data [63] Continuation-impart of Ser. No.I00,277, Dec. 21,

1970, abandoned.

[52] US. Cl. 242/4 A, 242/7.03 [51] Int. Cl. H0lf 41/08 [58] Field ofSearch 242/4 A, 4 R, 4 BE, 7.14,

[56] References Cited UNITED STATES PATENTS 2,l85,883 l/l940 Berger242/4 BE 2,978,l93 4/1961 Kelly 242/4 A 2,986,350 5/1961 Bugg 242/4 BE2,102,692 12/1937 Franz 242/4 R Primary Examiner-Billy S. TaylorAttorney, Agent, or Firm-Lee A. Strimbeck 57] ABSTRACT In toroidal corewinding apparatus, wherein the wire to be wound is stored as a helixwithin a hollow hoop and the hoop as it rotates through the coredispenses the wire from a point on the edge of its inner periphery; thehoop consists of a flexible hollow steel or plastic tube that can bemaintained in the shape of a distorted circle; e.g., an elongated ovalor racetrack shape, by guide wheels so that the hoop, for at least anappreciable portion of length on its periphery, moves in a straight lineas it passes through the core, thus permitting the diameter of thetubing forming the hoop to be larger.

Significant advantages of this invention are that: (a) the straight runpermits the wire to be drawn down tight on the core largely along itsline of travel; and (b) the wire can be wound on the core in eitherdirection by simply reversing the direction of rotation of the hoop.Also, two strands of wire can be payed out simultaneously from the hoop.This can be done in any conventional manner. For example, motor 20 canbe a reversible motor.

I PATENTEUIAY 21 I974 INVENTOR RiCHARD D. SEDGEWICK ATTORNEY PROCESS orWINDING CORES RELATED APPLICATION This application is a continuation, inpart, of Core Winding Device, U.S. Ser. No. 100,277, filed Dec. 21,1970, and now abandoned by the present inventor.

PREAMBLE It is customary to wind hollow cores such as toroidal coils andmotor strators by rotating a circular shuttle through the core. Theshuttle has the winding wire stored thereon by circumferentially windingit around its pheriphery. The shuttle is split to permit insertion andremoval of the core. However, the core must be first inserted into theshuttle and then the wire wound about the periphery of the shuttle,which is an awkward manner of operating and permits only wire sufficientfor one core to be placed on the shuttle. Also, the wire must be payedout of the rim of the shuttle not in line with the central plane ofrotation off the shuttle, which does not lend' itself to the winding oftoothed cores, such as stators.

PRIOR ART Some prior art devices proposed a modified core winding deviceusing a hollow tube in the shape of a closed circle. The wire to bewound is stored inside of the hollow tube in the form of a helix andpayed out from a point on the inner peripheral edge of the hoop. Sincethe hoop is circular, a point on its edge describes a circular path asit travels through the core which proscribes the cylindrical length ofthe core and/or the tube diameter of the hoop.

US. Pat. No. 3,466,518, Rotary Stepping Motors and Control SystemsTherefor, by V. Aylikci et a1. describes a motor construction that is ofparticular interest in that it has a toothed stator which is verydifficult to wind because the bore is relatively small and the spacingsor gaps between the stator poles are quite fine, calling for preciseguidance of the winding wire as it is being passed through the gaps.Also, as shown in FIG. 1 of the patent, the cylindrical length of thestator can be quite long relative to the diameter of the bore.

THIS INVENTION This invention is an improvement of and contains the sameessential elements as the prior art; i.e., a hollow hoop holding in theinside of the hollow tube a supply of the winding wire as a helix andadapted to dispense the same as a strand from a point on its innerperiphery; guide means; e.g., idler and drive wheels, adapted to rotatethe hoop through a hollow core, means for positioning the core to bewound and means for'releasably tensioning the wire during eachrevolution of the hoop.

The improvement of this invention comprises constructing the hoop of atube of a flexible metal or plastic that can be constrained duringoperation by the guide means in the form of a distorted circle; e.g., anelongated oval or racetrack shape or D-shape. In this manner, the tubecan be made to move as a straight line as it passes through the corewhich, with elongated cores; e.g., cores with an unusually high lengthto bore ratio, permits the cross-sectional diameter of the tube to belarger and/or thicker walled. Thus, the tube can have a greater storagecapacity and/or can be stronger.

The hoop of this invention is made by bringing the ends of a resilientflexible tube; e.g., one of a steel, PVC, polypropylene, nylon,polytetrafluoroethylene and preferably an extruded polyethylene,together. The properties of the tube are such as to form a flexible ordestortable circle when otherwise unrestrained, except by having theends of the tube brought together. The wire is first placed in the tubeas by winding it on a rodshaped mandrel, having a diameter smaller by atleast two thicknesses of the wire than the inside of the hollow tube.The wire wound rod and the hollow tube are then lined up in a straightline end-to-end and the helix of wire is pushed off the rod into thetube, after which the ends of the tube can be brought together and heldtogether as with a plug to form a circle.

To mount the wire-filled tube, it is snapped into the guide means whichimpose on it the race track shape, the ends of the tube are spread andthe core is inserted therebetween, after which the ends are broughttogether and the core winding operation can commence.

THE DRAWING The drawing is a schematic side view in evaluation of theimproved apparatus of this invention.

DESCRIPTION Referring to the drawing, the apparatus comprises a hollowtube 10 restrained in a racetrack form by means of idler wheels 11 anddrive wheels 12, which are suitably grooved at their peripheries toaccommodate the diameter of the tube. Tube 10 contains inside the finewire in the form of a helix and a strand 13 of the wire is payed out ata point 14 on the inner periphery of the tube, as through a plug 10atapped with a fine inwardly directing hole and adapted to maintain sometension on wire 13. Plug 10a press fits into both ends of the tube andkeeps them aligned and together.

The stator 15 to be wound is suitably rigidly mounted by means not shownas by a clamp. If the ends of the tube are firmly held together, as byplug 10a being threaded therein, the tube can be maintained in thedesired racetrack shape by two internal wheels in the same manner as aband saw, provided the wheels are split in the middle along the plane ofrotation to permit passage of wire 13.

As illustrated, tube 10 is driven around the track provided by the guidewheels by means of a motor 20 driving drive wheel 12 through a beltdrive 21, with the adjacent wheels being driven therefrom via belts 22and 23.

As is known, wire 13, during each revolution of hoop 10, is engaged by atension means 16 which holds the wire relatively firmly until it ispulled taut against the stator 15, at which time the wire 13 slipsthrough means 16. Means 16 can comprise two facing flat clutch-likepads, spring loaded to provide the necessary restraint. The pads arelarge enough and exert sufficient restraint so that the leading end ofthe wire is taut as it enters the stator.

Of course, it is not required that the sides of the moving tube becaused to move in a straight line except as it passes through the core.For example, the side opposite the core can be caused to move or beflexed inwardly in a curve to increase the effect length of the tubewithin the boundaries of the support frame, and/or also to increase thetension on the wheels engaging the tube. In this connection, guidewheels can be also placed on the inner periphery of the distortedcircular shape as desired. Alternatively, the hoop can be maintained ina rounded D shape. In some cases, guide tubes or funnels instead ofwheels can be used to position or direct the hoop.

In addition to the ease of operation and the increase in the number ofwindings for each time a new amount of wire must be stored, theapparatus of this invention has the significant advantage that whenproperly designed, the straight line run through the core permits thepull on the loop of wire placed on the core to be largely along thestraight line of travel of the tube; i.e., along the longitudinal axisof the core, and not at any significant angle thereto. Thus, as the loopof wire is drawn tight, it is required to pass over a lesser number ofsharp comers of the core. The wire can then be drawn tighter with lessresistance and opportunity for chafing, and this permits more turns tobe placed on a toothed stator having a limited slot area.

Two helixes of the core-winding wire can be stored inside of the hollowtube, one in one end, and one in the other end, and can then be payedout simultaneously from the hoop as it rotates in the guide means.

The use of flexible tube of this invention allows the apparatus to windin either direction; i.e., it can reverse wind, without any change inthe set-up. This can be done in any conventional manner. For example,motor 20 can be a reversible motor. A conventional shuttle cannot dothis as the wire is wound around the circumference in one directiononly. This reverse winding feature permits the establishment of desiredmagnetic polarities between interconnected windings without the need tosolder or connect leads from each winding; i.e., the number ofconnections required between winding leads can be significantly reducedby reverse winding. For example, with reference to FIG. 5(b) of theAlylikci patent, showing one way of connecting windings in a toothedstator, at least one-half or 12 lead ends can be eliminated by reversewinding in accordance with the present invention.

EXAMPLE The core wound was a 12 toothed laminated stack stator. It had aheight of 2% inches, and CD. of 2 inches, and a bore of inches. Thestator had 12 teeth approximately 3/32 inches wide each, which left 12gaps about 1/32 inches wide each through which the wire entered.

The hoop consisted of an extruded polyethylene tube of 2% inches O.D.,inches [.D. and feet long. Eight guide wheels are used, three of whichwere drive wheels and each of which had a diameter at the groove line of6 inches. The guide wheels maintained the tube in a racetrack shape andwere equally spaced thereabout. The radius of curvature of the ends ofthe racetrack was 12 inches. The total travel per revolution of the tubewas 10 feet. The tube was rotated at a rate of revolutions per minute.

The wire wound was No. 30, 100 turns per slotted section of the statorbeing required. Over 300 feet of this wire could be stored as a helix inthe polyethylene tube at one time.

I claim:

1. A process of winding a filament toroidly onto a hollow cylindricalcore, comprising, in combination, the steps of: i

a. providing a flexible hollow tube which, when the ends thereof arebrought together, is rigid enough to form a circular hoop if the tube isotherwise unrestrained but which is flexible enough to accept distortionof said hoop into an elongated noncircular shape;

b. loading said tube with a filament in the form of a helix runningalong the length of said tube;

c. inserting said tube through a hollow cylindrical core and bringingthe ends of said tube together;

d. mounting for rotation and constraining said tube into an elongatednon-circular shape with a straight run connected by curved ends, bymeans of guides mounted on a frame, at least one of which guides is arotating drive-guide;

e. guiding an end of said filament through a point on the innerperiphery of said elongated non-circular shape and restraining said end;

f. positioning and mounting said hollow cylindrical core to said frameso that said straight run passes therethrough; and

g. rotating said drive-guide and thereby rotating and feeding said tubethrough said hollow cylindrical core and winding said filament toroidlythereon as the same pays out from said point on the inner periphery.

2. The process of claim 1 comprising in addition:

1. during step (b), placing a second helix of said filament in saidtube:

2. at step (e), guiding an end of the filament of said helix through asecond point on said inner periphcry; and

3. during step (g), simultaneously winding the filament from said helixonto said hollow cylindrical core.

3. The process of claim 1 comprising the additional step of:

h. during at least part of the winding cycle, reversing the direction ofrotation of said tube and winding said filament toroidly onto saidhollow cylindrical core oppositely from the first direction of winding.

1. A process of winding a filament toroidly onto a hollow cylindricalcore, comprising, in combination, the steps of: a. providing a flexiblehollow tube which, when the ends thereof are brought together, is rigidenough to form a circular hoop if the tube is otherwise unrestrained butwhich is flexible enough to accept distortion of said hoop into anelongated noncircular shape; b. loading said tube with a filament in theform of a helix running along the length of said tube; c. inserting saidtube through a hollow cylindrical core and bringing the ends of saidtube together; d. mounting for rotation and constraining said tube intoan elongated non-circular shape with a straight run connected by curvedends, by means of guideS mounted on a frame, at least one of whichguides is a rotating drive-guide; e. guiding an end of said filamentthrough a point on the inner periphery of said elongated non-circularshape and restraining said end; f. positioning and mounting said hollowcylindrical core to said frame so that said straight run passestherethrough; and g. rotating said drive-guide and thereby rotating andfeeding said tube through said hollow cylindrical core and winding saidfilament toroidly thereon as the same pays out from said point on theinner periphery.
 2. The process of claim 1 comprising in addition:
 2. atstep (e), guiding an end of the filament of said helix through a secondpoint on said inner periphery; and
 3. during step (g), simultaneouslywinding the filament from said helix onto said hollow cylindrical core.3. The process of claim 1 comprising the additional step of: h. duringat least part of the winding cycle, reversing the direction of rotationof said tube and winding said filament toroidly onto said hollowcylindrical core oppositely from the first direction of winding.